Nguyen Chi-Ngon, Simanski Olaf, Kähler Ralf, Schubert Agnes, Janda Matthias, Bajorat Jörn, Lampe Bernhard
Department of Telecommunications and Control Engineering, Cantho University, Cantho, Vietnam.
Comput Methods Programs Biomed. 2008 Feb;89(2):153-61. doi: 10.1016/j.cmpb.2007.03.005. Epub 2007 Apr 18.
In order to improve the intraoperative applications, this paper presents the advantages of using Guyton's model in hypotensive control system development. In this system, the mean arterial pressure is decreased and maintained at a low level during anaesthesia by controlling sodium nitroprusside infusion rate. The key of the study is to develop a physiological model of cardiovascular dynamics to present the mean arterial pressure response to sodium nitroprusside, which was considered as a linear model in most of known blood pressure control systems. Being linear, the previous models cannot accurately mimic a physiological system of human circulation, especially at deep hypotensive control with strong reaction of the body. The enhanced model in this study was modified based on Guyton's model of human circulation. It is useful to design a PID controller, which allows studying and handling the wide range of the body sensitivities. This model is also helpful for studying the behaviors of patients under anaesthesia conditions, such as the perfusion of organs and the reaction of the body at hypotensive state. A fuzzy gain scheduler and a supervising algorithm were also developed for online tuning the controller to handle the behavior of the body. The control system was tested on 25 experiments on seven pigs in the animal laboratory. Simulation and experiment results proved the usefulness of Guyton's model in control system design which can present the dynamical response of blood pressure in the circulation under and after hypotensive control. The results also indicated the safety and stability of the controller.
为了改善术中应用，本文介绍了在低血压控制系统开发中使用盖顿模型的优势。在该系统中，通过控制硝普钠输注速率，在麻醉期间将平均动脉压降低并维持在较低水平。该研究的关键是建立心血管动力学的生理模型，以呈现平均动脉压对硝普钠的反应，在大多数已知的血压控制系统中，这被视为线性模型。由于是线性的，先前的模型无法准确模拟人体循环的生理系统，尤其是在深度低血压控制且身体反应强烈的情况下。本研究中的增强模型是在盖顿人体循环模型的基础上进行修改的。设计一个PID控制器很有用，它可以研究和处理广泛的身体敏感度。该模型也有助于研究麻醉条件下患者的行为，如器官灌注和低血压状态下身体的反应。还开发了一种模糊增益调度器和一种监督算法，用于在线调整控制器以处理身体的行为。该控制系统在动物实验室对7头猪进行了25次实验测试。仿真和实验结果证明了盖顿模型在控制系统设计中的有用性，它可以呈现低血压控制期间及之后循环中血压的动态反应。结果还表明了控制器的安全性和稳定性。
